Idler pulley missing?

hi all, just wondered if there’s meant to be a lower idler pulley here between the crank pulley and alternator pulley. There’s a hole which is threaded. The belt seems the slap about a lot in this area. It’s a 2004 1.9d with power steering, no air con. Also if there is, what is roughly the size of it so I know which one to buy. Many thanks 

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